If you have something to bend metal you can buy the parts and do it yourself. I think often one fails to value their time into building things. The only cavyot to that is if the items cost is hugely expensive to buy vs your build cost. If you calculate in time cost it gets hard to build stuff unless that's what gives you happiness. Then it really is muted. Pellet hoppers are fairly simple if you have the tools to work with. Only need a PID cintroler to manage it.

I am contemplating this as well. I don't mind making the hopper itself. Could be made from sheet metal or even a bucket. The hard part for me would be wiring up a motor, auger, and PID controller for controlling temps and feed speed. I'd even be curious about a gravity fed operation where you just adjust the feed rate from a turnstile end with a PID to allow flow down into the fire pot